1. Field of the Invention
The present invention relates to an engine cooling system including a water pump for circulating cooling water in order to cool the engine. Furthermore, a thermostat is provided in the water pump in such a manner as to be openable/closable depending on the temperature of cooling water.
2. Description of Related Art
An engine cooling system of this type has been known, for example, from Japanese Patent No. 2560186.
In the above-described related art system, the casing of a water pump is composed of a pump body and a pump case fastened to the pump body. A thermostat having a portion protruding into the pump case is held between the pump cover and a thermostat cover fastened to the pump case in such a manner as to cover the thermostat. As a result, the prior art system requires the pump cover, the pump case, and the thermostat cover for providing the thermostat in the water pump. This causes a problem in that the number of parts is increased, thereby increasing the cost, weight and the number of assembling steps.